전자부품 데이터시트 검색엔진 |
|
DS42587 데이터시트(PDF) 19 Page - Advanced Micro Devices |
|
DS42587 데이터시트(HTML) 19 Page - Advanced Micro Devices |
19 / 58 page DS42587 19 SecSi (Secured Silicon) Sector Flash Memory Region The SecSi (Secured Silicon) Sector feature provides a Flash memory region that enables permanent part identification through an Electronic Serial Number (ESN). The SecSi Sector is 64 Kbytes in length, and uses a SecSi Sector Indicator Bit to indicate whether or not the SecSi Sector is locked when shipped from the factory. This bit is permanently set at the factory and cannot be changed, which prevents cloning of a factory locked part. This ensures the security of the ESN once the product is shipped to the field. AMD offers the device with the SecSi Sector either fac tor y lock ed or customer lock able. T he fac - tory-locked version is always protected when shipped from the factory, and has the SecSi Sector Indicator Bit permanently set to a “1.” The customer-lockable version is shipped with the unprotected, allowing cus- tomers to utilize the that sector in any manner they choose. The customer-lockable version has the SecSi Sector Indicator Bit permanently set to a “0.” Thus, the SecSi Sector Indicator Bit prevents customer-lockable devices from being used to replace devices that are factory locked. The system accesses the SecSi Sector through a command sequence (see “Enter SecSi Sector/Exit SecSi Sector Command Sequence”). After the system has written the Enter SecSi Sector command se- quence, it may read the SecSi Sector by using the addresses normally occupied by the boot sectors. This mode of operation continues until the system issues the Exit SecSi Sector command sequence, or until power is removed from the device. On power-up, or following a hardware reset, the device reverts to send- ing commands to the boot sectors. Factory Locked: SecSi Sector Programmed and Protected At the Factory In a factory locked device, the SecSi Sector is pro- tected when the device is shipped from the factory. The SecSi Sector cannot be modified in any way. The device is available preprogrammed with a random, se- cure ESN only In devices that have an ESN, the Top Boot starting ad- dress of the ESN will be at the bottom of the lowest 8 Kbyte boot sector at addresses 1F8000h–1F8007h in word mode (or addresses 3F0000h–3F000Fh in byte mode). Customer Lockable: SecSi Sector NOT Programmed or Protected At the Factory If the security feature is not required, the SecSi Sector can be treated as an additional Flash memory space, expanding the size of the available Flash array by 64 Kbytes. The SecSi Sector can be read, programmed, and erased as often as required. Note that the acceler- ated programming (ACC) and unlock bypass functions are not available when programming the SecSi Sector. The SecSi Sector area can be protected using one of the following procedures: s Write the three-cycle Enter SecSi Sector Region command sequence, and then follow the in-system sector protect algorithm as shown in Figure 2, ex- cept that RESET# may be at either V IH or VID. This allows in-system protection of the without raising any device pin to a high voltage. Note that this method is only applicable to the SecSi Sector. s Write the three-cycle Enter SecSi Sector Region command sequence, and then use the alternate method of sector protection described in the “Sec- tor/Sector Block Protection and Unprotection”. Once the SecSi Sector is locked and verified, the sys- t e m m u st w r it e t h e Ex it Se cSi Se ct or R e g i o n command sequence to return to reading and writing the remainder of the array. The SecSi Sector protection must be used with cau- tion since, once protected, there is no procedure available for unprotecting the SecSi Sector area and none of the bits in the SecSi Sector memory space can be modified in any way. Hardware Data Protection The command sequence requirement of unlock cycles for programming or erasing provides data protection against inadvertent writes (refer to Table 12 for com- mand definitions). In addition, the following hardware data protection measures prevent accidental erasure or programming, which might otherwise be caused by spurious system level signals during V CC power-up and power-down transitions, or from system noise. Low VCC Write Inhibit When VCC is less than VLKO, the device does not ac- cept any write cycles. This protects data during VCC power-up and power-down. The command register and all internal program/erase circuits are disabled, and the device resets to reading array data. Subse- quent writes are ignored until VCC is greater than VLKO. The system must provide the proper signals to the control pins to prevent unintentional writes when VCC is greater than VLKO. Write Pulse “Glitch” Protection Noise pulses of less than 5 ns (typical) on OE#, CE#f or WE# do not initiate a write cycle. Logical Inhibit Write cycles are inhibited by holding any one of OE# = V IL, CE#f = VIH or WE# = VIH. To initiate a write cycle, |
유사한 부품 번호 - DS42587 |
|
유사한 설명 - DS42587 |
|
|
링크 URL |
개인정보취급방침 |
ALLDATASHEET.CO.KR |
ALLDATASHEET 가 귀하에 도움이 되셨나요? [ DONATE ] |
Alldatasheet는? | 광고문의 | 운영자에게 연락하기 | 개인정보취급방침 | 링크교환 | 제조사별 검색 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |